Java - 错误：无法找到或加载主类

Question

我想运行一个图形用户界面我编程，并遇到一个错误，当我尝试运行我的程序在Eclipse中运行。以下消息显示在控制台中：“错误：无法找到或加载主类”。我的java文件是在默认的包中，并且我在网上有解决和搜索小问题的小问题。任何帮助将非常感激！谢谢。

import java.awt.event.ActionEvent; 



import java.awt.event.ActionListener; 
import java.awt.event.MouseEvent; 
import java.awt.event.MouseListener; 
import java.awt.event.MouseMotionListener; 
import java.awt.Color; 
import java.awt.Graphics; 

import javax.swing.BoxLayout; 
import javax.swing.ImageIcon; 
import javax.swing.JButton; 
import javax.swing.JCheckBox; 
import javax.swing.JColorChooser; 
import javax.swing.JFrame; 
import javax.swing.JLabel; 
import javax.swing.JPanel; 
import javax.swing.JRadioButton; 
import javax.swing.JTextArea; 
import javax.swing.event.ChangeEvent; 
import javax.swing.event.ChangeListener; 

public class myWindow implements ActionListener, MouseListener,   MouseMotionListener, ChangeListener { 
    private int width, height; 

    private JFrame myWindow; 
    private JPanel panel1, panel2, panel3, panel4, panel5; 
    private JButton button1, button2, button3; 
    private JLabel label1; 
    private JCheckBox checkbox1; 
    private JRadioButton radiobutton1; 
    private JColorChooser colorChooser; 

    private boolean mousePressed; 
    private int old_x, old_y; 
    private Color color; 

    public static void main(String[] args) { 
     myWindow w = new myWindow(); 


    } 

    public myWindow() 
    { 
     width = 600; 
     height = 400;  
     mousePressed = false; 
     old_x = 0; 
     old_y = 0; 
     color = new Color(0, 0, 0); 
     myWindow = new JFrame(); 
     myWindow.setSize(width, height); 
     myWindow.setLocation(100, 100); // Sets location of the window 
     myWindow.setTitle("Window title"); 

     myWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Terminates the program on close 

     button1 = new JButton("Button 1"); 
     button2 = new JButton("Button 2"); 
     button3 = new JButton("Button 3"); 

     checkbox1 = new JCheckBox("Check"); // Creates check box 
     radiobutton1 = new JRadioButton("Radio Button"); // Creates radio button 

     colorChooser = new JColorChooser(); 

     panel1 = new JPanel(); // Creates panel 
     panel2 = new JPanel(); 
     panel3 = new JPanel(); 
     panel4 = new JPanel(); 
     panel5 = new JPanel(); 
     panel1.setLayout(new BoxLayout(panel1, BoxLayout.Y_AXIS)); 

     panel1.add(panel2); // Adds panel 
     panel1.add(panel3); 

     panel2.setLayout(new BoxLayout(panel2, BoxLayout.X_AXIS)); // Changes to make buttons vertical 
     panel2.add(panel4); 
     panel2.add(panel5); 

     panel3.add(colorChooser); 

     panel4.setLayout(new BoxLayout(panel4, BoxLayout.Y_AXIS)); 
     panel4.add(button1); // Adds button to stated panel 
     panel4.add(button2); 
     panel4.add(button3); 
     panel4.add(checkbox1); 
     panel4.add(radiobutton1); 
     myWindow.add(panel1); 

     label1 = new JLabel(new ImageIcon("res/images/dota2.jpg")); // Gathers the image 
     panel5.add(label1); 


     button1.addActionListener(this); 
     button2.addActionListener(this); 
     button3.addActionListener(this); 
     label1.addMouseListener(this); 
     label1.addMouseMotionListener(this); 
     colorChooser.getSelectionModel().addChangeListener(this); 

     myWindow.setVisible(true); //Makes window visible 
    } 

    public void actionPerformed(ActionEvent e) { 
     if(e.getSource() == button1) 
     { 
      System.out.println("Button 1 pressed."); 
      button1.setText("Button 1 pressed"); 
     } 
     else if(e.getSource() == button2) 
     { 
      System.out.println("Button 2 pressed."); 
      button2.setText("Button 2 pressed"); 
     } 
     else if(e.getSource() == button3) 
     { 
      System.out.println("Button 3 pressed."); 
      button3.setText("Button 3 pressed"); 
     } 

    } 

    public void mouseClicked(MouseEvent e) { 
     if(e.getSource() == label1) 
     { 
      System.out.println("Mouse clicked."); 
      System.out.println("(x,y) = (" + e.getX() + ", " + e.getY() + ")"); 
      Graphics g = label1.getGraphics(); 
      g.drawOval(e.getX(), e.getY(), 3, 3); 

     } 
    } 

    public void mousePressed(MouseEvent e){ 
     System.out.println("mousePressed = " + mousePressed); 
     Graphics g = label1.getGraphics(); 
     g.setColor(color); 
     g.drawOval(e.getX(), e.getY(), 3, 3); 
     mousePressed = true; 
     old_x = e.getX(); 
     old_y = e.getY(); 
    } 


    public void mouseDragged(MouseEvent e) { 
     System.out.println("mousePressed = " + mousePressed); 
     if(mousePressed) 
     { 
      Graphics g = label1.getGraphics(); 
      // g.drawOval(e.getX(), e.getY(), 3, 3); 
      g.setColor(color); 
      g.drawLine(old_x, old_y, e.getX(), e.getY()); 
      old_x = e.getX(); 
      old_y = e.getY(); 
     } 
    } 

    public void mouseMoved(MouseEvent e) { 
     if(mousePressed) 
     { 
      Graphics g = label1.getGraphics(); 
      g.setColor(color);        //I DID THIS MYSELF 
      g.drawOval(e.getX(), e.getY(), 3, 3); 
     } 
    } 

    public void mouseEntered(MouseEvent e) { 
     // TODO Auto-generated method stub 

    } 

    public void mouseExited(MouseEvent e) { 
     // TODO Auto-generated method stub 

    } 

    public void mouseReleased(MouseEvent e) { 
     mousePressed = false; 
     Graphics g = label1.getGraphics(); 
     g.setColor(color); 
     g.drawOval(e.getX(), e.getY(), 3, 3); 
     System.out.println(" Mouse released."); 

    } 

    public void stateChanged(ChangeEvent e) { 
     color = colorChooser.getColor(); 

    } 



} 

Answer 1

run my program in Eclipse

在Eclipse中，转到运行 - >运行配置。在Main选项卡下：Main Class定义包含您希望运行的主要方法的类。点击搜索按钮。 Eclipse将搜索包含可选择运行的主要方法的类。从那里你可以申请或选择直接运行